Ah, I figured out what the problem was. So, after scouring the internet for an hour, I happened on an old reddit post mentioning a similar problem that was a result of using TES5Edit. To put it simply, I used TES5 to clean Dragonborn.esm and somehow in doing so deleted the assets for this location in the game. Weird. To fix it, just swapped out the cleaned dragonborn.esm for the backup and presto! The lake of death is gone.